Shulou(Shulou.com)06/01 Report--

This article mainly explains "what are the concepts of database backup". Interested friends may wish to take a look at it. The method introduced in this paper is simple, fast and practical. Let's let the editor take you to learn "what are the concepts of database backup"?

The concept of backup full backup (Full Backup) backs up all selected folders and does not rely on the archive properties of files to determine which files are backed up. During the backup process, any existing tags are cleared and each file is marked as backed up. In other words, clear the archive properties. A complete copy of all data or applications at a point in time. In practical application, the whole system is completely backed up with a magnetic tape. Advantage: with only one tape, you can recover the lost data. As a result, the recovery time of the system or data is greatly accelerated. Disadvantages: there is a lot of duplicate information in the backup data in each full backup tape; in addition, due to the large amount of data that needs to be backed up each time, the backup takes a long time. Differential backup (Differential Backup): differential backup refers to the backup of those files that have been added or modified during the period from a full backup to the differential backup. When we restore, we only need to restore the first full backup and the last differential backup. Back up data that has changed since the last full backup. During a differential backup, only those selected files and folders that are marked are backed up. It does not clear the mark, that is, it is not marked as backed up after the backup. In other words, the archive properties are not cleared. Advantages: differential backup not only avoids the shortcomings of the other two backup strategies, but also has their own advantages. First, it has the advantages of short incremental backup time and saving disk space; second, it has the characteristics of less tape needed for full backup recovery and short recovery time. The system administrator only needs two tapes, the full backup tape and the differential backup tape the day before the disaster, to restore the system. Incremental backup (Incremental Backup): backing up data that has changed since the last backup, including full backup, differential backup, incremental backup. During an incremental backup, only marked selected files and folders are backed up, which clears the markup, that is, marking files after backup, in other words, clearing archive attributes. After a full backup or a previous incremental backup, each subsequent backup only needs to back up the files that have been modified compared to the previous one. This means that the objects of the first incremental backup are the files added and modified after the full backup, the objects of the second incremental backup are the files added and modified after the first incremental backup, and so on. Advantages: 1. There is no duplicate backup data, so the amount of data backed up is small. two。 The small amount of data means that the backup time is very short. Disadvantages: 1. The data recovery of incremental backup is troublesome. Must have the last full backup and all incremental backup tapes (if one of the tapes is lost or damaged, the recovery will fail) 2. The restore must be reversed one by one in the order from full backup to incremental backup, so this greatly increases the recovery time. At this point, I believe you have a deeper understanding of "what is the concept of database backup?" you might as well do it in practice. Here is the website, more related content can enter the relevant channels to inquire, follow us, continue to learn!

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.